#main {
  height: 100%;
  padding: 0 20px;
}
.header {
  height: 55px;
  border-bottom: 1px solid #f2f2f2;
  line-height: 55px;
}
.header .btn {
  margin-right: 8px;
  margin-top: 0;
  display: inline-block;
  width: 75px;
  text-align: center;
  line-height: 30px;
  height: 30px;
  color: #FFFFFF;
  cursor: pointer;
  font-size: 14px;
  border-radius: 3px;
  font-size: 12px;
}
.header .btn:first-child {
  background: linear-gradient(130deg, rgb(241, 213, 77) 0%, rgb(239, 158, 73) 100%);
}
.header .btn:nth-child(2) {
  background: linear-gradient(130deg, rgb(68, 207, 171) 0%, rgb(151, 132, 251) 100%);
}
.header .btn:nth-child(3) {
  background: linear-gradient(130deg, rgb(68, 207, 171) 0%, rgb(151, 132, 251) 100%);
}
.content {
  padding-top: 20px;
}
.content .title .topic {
  font-size: 22px;
  color: #303133;
  font-weight: bold;
}
.content .title  .collectBtn {
  padding-left: 10px;
  border-radius: 22px;
  border: 1px solid #f2f2f2;
  padding-right: 10px;
  width: 75px;
  display: inline-block;
  height: 30px;
  line-height: 30px;
  text-align: center;
  font-size: 12px;
  margin-left: 20px;
}
.collectBtn {
  cursor: pointer;
}
.courseType {
  padding-top: 10px;
  display: flex;
  justify-content: space-between;
}
.courseType .type {
  width: 200px;
  display: inline-block;
}
.introduce,.article,.attachment,.video,.file,.directory {
  padding-top: 30px;
  display: flex;
}

.desc {
  display: inline-block;
  width: 65px;
}
.flexRight {
  flex: 1;
}
.fileBox {
  cursor: pointer;
  padding-bottom: 5px;
}
.fileBox:hover {
  color: #409EFF;
}
.el-timeline {
  margin: 0;
  font-size: 14px;
  list-style: none;
}
.el-timeline-item {
  position: relative;
  padding-bottom: 20px;
}
.el-timeline-item__tail  {
  position: absolute;
  left: 4px;
  height: 100%;
  border-left: 2px solid #e4e7ed;
}
.el-timeline .el-timeline-item:last-child .el-timeline-item__tail {
  display: none;
}
.el-timeline-item__node {
  position: absolute;
  border-radius: 50%;
  display: flex;
  justify-content: center;
  align-items: center;
  left: -1px;
  width: 12px;
  height: 12px;
  background-color: #e4e7ed;
}
.el-timeline-item__node_select {
  background-color: rgb(11, 189, 135);
}
.el-timeline-item__wrapper {
  position: relative;
  padding-left: 28px;
  top: -3px;
  color: #409eff;
}
.el-timeline-item__wrapper:hover {
  color: #66b1ff;
}
.chapter:hover {
  cursor: pointer;
  border-bottom: 1px solid #409eff;
}
.complete {
  color: #606266;
}
.picture-preview-wrap {
  position: absolute;
  width: 100%;
  background-color: rgba(0,0,0,.5);
  top: 0;
  left: 0;
  z-index: 9999;
  height: 100%;
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-pack: center;
  -ms-flex-pack: center;
  justify-content: center;
  -webkit-box-align: center;
  -ms-flex-align: center;
  align-items: center;
}
.picture-list {
  width: 95%;
  height: 100%;
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-pack: center;
  -ms-flex-pack: center;
  justify-content: center;
  -webkit-box-align: center;
  -ms-flex-align: center;
  align-items: center;
}
.img-box {
  width: 100%;
  height: 90%;
  position: relative;
  display: inline-block;
  overflow: hidden;
}
.img-box img {
  transform: scale(1);
  position: absolute;
  width: 100%;
  height: 100%;
  vertical-align: top;
  -o-object-fit: contain;
  object-fit: contain;
}
.icon-dlose {
  position: absolute;
  top: 0;
  right: 0;
  width: 50px;
  height: 50px;
  text-align: center;
  line-height: 50px;
  font-size: 40px;
  color: #FFFFFF;
  cursor: pointer;
}